As 3D movies become popular, display devices to watch 3D images at home have been developed and launched in the market. The 3D image display device typically uses the frame sequential scheme (also called “time-divisional scheme”) which alternately switches and displays a left-eye image, which is viewed by the left eye, and a right-eye image, which is viewed by the right eye.
A projector used in a movie theatre, a TV device used at home or a display device of a personal computer is exemplified as the display device using the frame sequential scheme or the time-division scheme. These 3D display devices alternatively switch and display the left-eye image and the right-eye image. The viewer watches the displayed images on the 3D display device through an eyewear device (generally called “3D active shutter eyewear”).
The display device transmits synchronization signals in synchronization with the display of the left-eye and/or right-eye images. For example, infrared (IR) signals or radio (RF) signals are used as the synchronization signals. In synchronization with the display of the left-eye image, the eyewear device, which receives the synchronization signal, opens the left shutter situated in front of the left eye, and closes the right eye shutter situated in front of the right eye. In synchronization with the display of the right-eye image, the eyewear device also opens the right shutter and closes the left shutter. Thus, the light from the left-eye image transmits only to the left eye, and the light from the right-eye image transmits only to the right eye.
Liquid crystal shutters are typically used as the left and right shutters of the eyewear device. The left and right liquid crystal shutters open and close in response to the received synchronization signal. The synchronization signals transmitted from the display device are used to notify the eyewear device of timings to open or close the left and right liquid crystal shutters in synchronization with the display of the left-eye or right-eye image (e.g. see Patent Document 1 or 2).
An eyewear device, hereafter “theatre eyewear device”, which is used in a movie theatre that shows 3D movies, and another eyewear device, hereafter “domestic eyewear device”, which is used for a domestic TV device or a display device for a domestic personal computer that displays 3D images (hereafter called “3D display devices”), are manufactured on the basis of different specifications, respectively. Therefore, a user may use a single eyewear device to view only the 3D movie shown in the movie theatre or the 3D image displayed on the home 3-D display device.
When a domestic eyewear device is purchased, a user may actually try on various eyewear devices to select an eyewear device which fits best. On the other hand, a theatre eyewear device is not always perfectly fit a user, who actually wears it, although the theatre eyewear device is designed to fit many individuals. If images are viewed at the theatre by the user wearing the imperfectly fit eyewear device, the user may insufficiently concentrate on the images shown in the theatre.
If the user uses own eyewear device in a theatre, the user may comfortably view the images, but as described above, there is no common or unified specifications about the synchronization signals at this moment. The theatre 3D display device and the home 3D display device transmit synchronization signals in conformity with different specifications from each other (different codes, different transmission timings) of the eyewear devices, respectively. Eyewear devices are also inherently programmed so that the shutters are opened and closed according to the specifications of the transmitted synchronization signals.
In terms of maintaining image quality, which is provided to viewers, and compatibility with conventional apparatuses, it is undesirable to change the codes and timings of the synchronization signals, which are optimized for conventional 3D display devices and corresponding eyewear devices. Therefore, it is difficult under the current situation to change the specifications of the synchronization signals which are inherently used in theatres and in houses, respectively.
Patent Document 1: JP 11-98538 A
Patent Document 2: JP 2000-36969 A